Cancer arises in many forms from many different cellular origins, such as cells of the central nervous system, bone, breast, skin, thyroid, lung, liver, pancreas, prostate, soft tissues, and blood. But even among patients with histologically similar malignancies, researchers and clinicians have long recognized distinct heterogeneity in terms of clinical course and response to particular therapies, which has greatly complicated traditional treatment efforts. More recently, however, genetic and molecular analyses have begun to reveal the underpinnings for that heterogeneity. Through such studies, it has become clear that individual cancers classified under the same diagnostic umbrella often exhibit striking diversity in terms of their particular genetic alterations and gene expression patterns, and that those molecular differences frequently correlate with outcomes observed during treatment.
Efforts have thus begun aimed at identifying molecular traits that will predict responsiveness and/or resistance to available treatment options for a given subject. With such knowledge, a doctor attending to different patients diagnosed with nominally similar tumors could tailor individual treatment plans for those patients based on detectable molecular differences between their cancer cells—an approach often referred to as “personalized medicine.” The development of robust methods for the targeted treatment of patients suffering from cancer and other disorders holds great promise for improving standard medical care.